Who will reign supreme when hotties Robert Pattinson and Zac Efron battle for the Best Kiss award at the MTV Movie Awards this weekend? (Sure, they’re also up against scenes from Slumdog Millionaire, I Love You Man, Milk and Wanted, but who can really compete with these two leading men?) We asked Andrea Demirjian, the author of Kissing: Everything You Ever Wanted to Know About One of Life’s Sweetest Pleasures, to critique their performances and choose her personal favorite in a face-off between the two.

Efron and co-star Vanessa Hudgens got points for just how genuine their on-screen smooch in High School Musical 3 seemed. It doesn’t hurt that the pair isn’t acting—they’re also a couple when the cameras stop rolling. “What is evident is that they are very much in love,” Demirjian said. “It’s tender, it’s soft, it’s gentle. You can tell how much he loves her because he’s smiling as he kisses her, because he’s just so happy.” She also approved of their chemistry and “body interaction,” and called the scene “one of the sweetest things I’ve seen in a long time.”

When it comes to Robert Pattinson and Kristen Stewart’s forbidden vampire-on-human kiss, Demirjian was impressed. “I looked at this one a few times, cuz I was like, ‘whoa!’” she laughed. “The kiss was so sexy, just the way their lips were grazing against each other—it wasn’t deep-throat tongue kissing.” Part of the appeal of this silver-screen kiss is the tension, Demirjian said, which gave the eventual smooch “all the perfect makings of suspense and anticipation. And that makes a kiss more desirous.”

If you want to give someone a silver-screen-worthy snogging, Demirjian says her two basic tips are to slow down and keep it clean. “I always encourage people to enjoy kissing softly and gently,” she suggests. In other words: easy on the tongue wrestling. Don’t skip the dental floss, either. “You never know when a kiss is going to present itself,” she reminded. “A kiss can really get dinged on a technicality like bad breath.”

So which leading man does Demirjian think will reign supreme? “I wouldn’t necessarily compare them to one another, because they were two very different categories. One is sort of a beastly, supernatural thing versus two charmed kids in High School Musical,” she said. But Demirjian did give the kisses a star rating based on sexiness. Pattinson and Stewart scored a four-and-a-half out five, while Efron and Hudgens got “a four or three-and-a-half.” Guess we’ll just have to wait until Sunday to see if the MTV audience agrees with the expert! (Photo: WENN)